Door check



Nov. 12, 1968 P. LIOGIER 3,409,934

DOOR CHECK Filed Dec. 5, 1966 FiG/i FIG.2O

INVENTOR ATi-QRNEY Pierre Liogier United States Patent 3,409,934 DOOR CHECK Pierre Liogier, 54-56 Cours de la Liberte, Lyon, France Filed Dec. 5, 1966, Ser. No. 599,052 Claims priority, applic2ti7o8n France, Jan. 4, 1966, 4 6 7 Claims. (Cl. 1655) ABSTRACT OF THE DISCLOSURE Door check with dashpot assembly whose spring-loaded piston is rigid with a head having a chevron-shaped transverse groove which, in a closed-door position, points toward the axis of rotation of a shaft extending at right angles to the piston, this shaft being arranged to turn upon a swinging of the door carrying the door check; a roller mounted eccentrically on the shaft engages in the groove to displace the piston against its spring force whenever the door is opened. In the closed-door position, the roller rests at the vertex of the groove; after rotating through about 150 from this starting position, it approaches a zone of ineffectiveness of the restoring spring so that the door may be left open notwithstanding the closing force acting upon the piston.

The present invention relates to door checks.

Various types of such devices are known which ensure the closing either of single-acting doors towards the left or the right or of double-acting doors, but none of these known types is adapted to ensure the closing of any kind of door whatever.

The present invention obviates such drawback. It relates to a door check of the type having a braking piston whose rod is provided with a head having, on the one hand, on its upper surface a chevron-shaped transverse groove in which a roller is housed, this roller being eccentrically mounted on a shaft carrying an arm linking the door check with the door frame, and, on the other hand, on its lower surface a longitudinal groove inside which a finger fixed in the casing of said door check is adapted to slide.

According to a preferred embodiment of the door check of the invention, the above-mentioned grooved head is riveted to the rod of the braking piston, and the shaft carrying the connecting arm is rotatively guided by ball bearings which reduce substantially the frictional resistance opposing the rotation.

r The chevron-shaped transverse groove, WhlCh 1s engaged by the eccentric roller of the rotary shaft, offers the following advantages when the door is being opened or closed:

When the door is in its closed position, the restoring spring bearing upon the'piston is expanded, and the driving roller lies at the vertex of the chevron-shaped groove.

In this position, the vertex of the groove points toward the axis of the shaft, which is perpendicular to the direction of reciprocation of the spring-loaded piston; the two divergent branches of the groove form camming surfaces for converting a rotation of the shaft into a linear displacement of the piston and vice versa. As the door begins to open, the roller leaves the vertex and begins to compress the expanded spring at an initially slow rate which progressively increases with the moment arm at the point of contact between the roller and the groove surface. This moment arm reaches a maximum after a rotation of the shaft through almost 90, corresponding to a somewhat smaller swing of the door. When the roller has revolved through about 150, approaching its dead-center position, the moment arm becomes so short that the 3,409,934 Patented Nov. 12, 1968 spring force ceases to be effective and the door stops in whatever position it has been placed within a range of, say, to from its position of closure.

Thus, the countervailing force of the restoring spring rises during the first phase of the opening swing, when the door is thrust generally forwardly, and decreases at a point where the person walking through the doorway must push the door sideways to open it further. Because of the symmetrical positioning of the chevron-shaped groove with reference to the piston axis, this will be true whether the door is swung in or out.

The invention will be clearly understood from the following description given with reference to the appended diagrammatic drawing which illustrates, by way of nonlimiting example, an embodiment of the door check of the invention. In the drawing:

FIG. 1 is a top plan view of a door check according to my invention in longitudinal section;

FIG. 2 is a sectional view of same taken on the line 22 of FIG. 1, and

FIG. 3 is a set of diagrams illustrating the operation of the door check.

The door check shown in the drawing includes a piston 2 movable along an axis A inside a bushing 3 inserted in the casing 4. Piston 2 moves in one direction upon the opening of the door, and in the other direction under the action of a spring 5 previously compressed, this latter move taking place when the door is being closed; oil contained in a space 6 passes into the interior of casing 4 through a calibrated port 7 and channels, shown in part at 19, piston 2 and bushing 3, thus acting as a conventional dashpot assembly which slows down the closing motion of the door.

According to the invention, a head 9 is inserted into the casing 4 and riveted onto a rod 8 linked to the piston 2.

The head 9 is provided on its upper surface with a chevron-shaped transverse groove 10, and on its lower surface with a longitudinal groove 12. The upper groove 10 houses a roller 13 mounted eccentrically on a shaft 14; this shaft 14 is rotatably journaled in casing 4 by ball bearings 15 and provided at its outer portion with a square piece 16 forming a connection with an articulated arm (not shown) secured to the door frame.

The longitudinal groove 12 receives a finger 17 fastened to the inner lower wall of the casing 4 along the axis 0 of the shaft 14.

When the door carrying the door check is being opened, the shaft 14, is rotated about its axis 0 and drives the roller 13 which, by moving inside the chevronshaped groove 10, shifts the head 9 in the direction of the arrow 18. The head 9 can move only along its longitudinal axis since the finger 17 sliding along its groove 12 prevents said head from moving in any transverse direction.

The reverse motion takes place when the door is being closed, either by hand or automatically under the control of restoring spring 5.

The operation of my improved door check will now be explained in greater detail with reference to FIG. 3 which, in graphs (a), (b) and (c), ShOWs three successive positions of the eccentric coupling element 13 and groove 10 upon counterclockwise rotation of shaft 14 about axis 0 from the starting position illustrated in FIGS. 1 and 2. In position (a), roller 13 has just begun to leave the vertex of groove 10 and contacts the right-hand wall of the groove at a point whose surface normal It defines a short moment arm in with axis 0. As the roller continues on its orbit 0, it reaches position (b) in which the moment arm m is at its maximum; this also corresponds to a maximum counteracting torque exerted by the spring 5 upon the shaft 14 to oppose the opening swing of the door. Upon rotating through another 90, the roller 13 arrives at its dead-center position (c) in which the moment arm in disappears; even before reaching that point, e.g. after a rotation of about 150 from its starting position, the roller enters a zone in which the moment arm is so small that the spring 5 is unable to overcome the friction and inertia of the movable parts so that the door will remain in its open position whenever the roller lies between that point and a symmetrical point having the same moment arm, i.e. in the range of 150 to 210 which may correspond to a door swing of 100 to 140. Obviously, conditions are similar when the door is swung open in the opposite direction, with roller 13 revolving clockwise rather than counterclockwise in FIG. 3.

In the terminal piston position of FIGS. 1 and 2, the vertex of groove points toward axis 0 and the two branches of the groove on opposite sides of that vertex lie skew to this axis. Groove 10 always remains situated in the plane of orbit 0,

What I claim is:

1. A door check comprising a casing with a piston slidable therein along a first axis; spring means urging said piston toward a terminal position along said axis; a shaft journaled in said casing for rotation about a second axis transverse to said first axis, said shaft being connectable to a door frame for rotating about said second axis upon the swinging of a door, carrying said door check, with reference to said frame; a coupling member eccentrically mounted on said shaft for revolving about said second axis; and co-operating coupling means rigid with said piston forming a groove in the plane of revolution of said member, said groove being engaged by said member and having a portion lying skew to said first axis in said terminalposition of said piston.

2. A door check as defined in claim 1 wherein said groove is chevron-shaped, with a vertex pointing toward said second axis in said terminal position.

3. A door check as defined in claim 1 wherein said piston is part of a dashpot assembly in said casing.

4. A door check as defined in claim 1 wherein said casing is provided with ball bearings rotata-bly supporting said shaft.

5. A door check as defined in claim 1 wherein said cooperating coupling means comprises a rod joined to said piston and a head secured to said rod, said groove being formed on said head, said spring means being disposed between said piston and said head.

6. A door check as defined in claim 5 wherein said head is provided with a second groove extending in the direction of said first axis, said casing having a formation engaging in said second groove for guiding said head along said first axis.

7. A door check as defined in claim 6 wherein said head has a pair of opposite faces respectively provided with said grooves.

No references cited.

BOBBY R, GAY, Primary Examiner.

J. L. KOHNEN, Assistant Examiner. 

